A destructive malware Shamoon (or W32.Disttrack) was used in a large scale cyber-attack targeting the Middle East giant oil company "Saudi Aramco".
Read more here - http://pastebin.com/p5C4mCCD
W32.Disttrack is a new threat that is being used in specific targeted attacks against at least one organization in the energy sector. It is a destructive malware that corrupts files on a compromised computer and overwrites the MBR (Master Boot Record) in an effort to render a computer unusable. Symantec Security Response is continuing to analyze this threat and will post more information as it becomes available.
Read more here - http://www.symantec.com/connect/blogs/shamoon-attacks